With the development of 5G and data centers, the demand for optical modules is increasing day by day, and it is necessary to further reduce costs. Network equipment and optical modules are gradually decoupled. It will become a trend for module manufacturers to directly ship to 5G and data center customers. This trend will increase the difficulty of data center operation and maintenance. Take the commonly used 100G SR4/CWDM4 and LR4 as an example. When a fault occurs, network manufacturers and module manufacturers will have unclear problem definitions. If there is no effective unified management model, Module batch issues will be hard to spot. Therefore, the management of multi-type and multi-vendor modules will be a key issue in the network evolution process. As 400G/800G samples appear and are gradually shipped, new optical modules face higher requirements and challenges in terms of density, power consumption, performance, and stability. In the future, optical modules will be an important part of operation and maintenance management.
Regarding the operating status of the optical module, the SFF.8472 protocol specifies five key DDM information: operating temperature Temp, operating voltage Vcc, bias current Tx_ Bias, received optical power Rx_Power and transmitted optical power Tx_Power. At the same time, the agreement also stipulates that each optical module manufacturer can set the DDM range, and alarm the properties beyond the range.
The five attributes of DDM are all related to the degree of deterioration and the expected remaining life of the optical module. Therefore, DDM can be used to diagnose and warn the fault of the optical module, thereby providing a performance monitoring method for the system, which can help the system management to predict the life and isolation of the transceiver module. system failures and verify module compatibility in field installations.
Current Technical Problems
Usually, the optical power feedback control unit inside the optical module will control the transmitted optical power to a stable level. The optical power feedback control unit is realized by increasing the Tx_Bias of the laser, so the life of the laser can be predicted by monitoring the Tx_Bias of the laser. At the same time, the Tx_Bias of the laser is closely related to Temp and Vcc, and the influence of Temp and Vcc needs to be considered when setting the limit of Tx_Bias.
At present, the network management system can realize the timed collection of DDM, alarm according to the threshold range set by the manufacturer, and output the log. However, the DDM range set by the general manufacturer is relatively large, and the DDM-related attribute value has not yet reached the early warning value, and the degree of deterioration of the light module is enough to affect the business. In addition, the network management system uses the current value to compare with the DDM threshold range, lacks consideration of the DDM trend, and does not have the ability to predict optical module failures.
The optical power feedback control unit inside the optical module will control Tx_Power at a stable level, but as the laser ages, the quantum efficiency of the laser will decrease. Stable control of the power is achieved by increasing the Tx_Bias of the laser, so its lifetime can be predicted by monitoring the Tx_Bias of the laser. At the same time, the Tx_Bias of the laser is closely related to Temp and Vcc, and the influence of Temp and Vcc needs to be considered when setting the limit of Tx_Bias.
